I am interested if anybody has experience of Black start capability on a CCGT or in general.
Synchronisation apparently is achieved from a power island by the grid system becoming the "Incoming" reference and the Station busbar becoming the"On load reference". Normally on an infinite system the role is reversed. Could anybody clarify this and explain the theory behind this.

Many Thanks

 

By definition a generator with black start capability must be able to restart without a network connection. For a CCGT this usually achieved by having a diesel engine that can be used to run up the GT unit to speed and enable it to start. Having got the generator started it is not much use if it cannot be connected to start other generators in the network. Thus most black start generators would also be able to have a network and at least one other generator connected to it, and must be able to supply the power needed to start the other generator without experiencing overloads or low voltage condition. In general the black start unit will be co-located with the other generators it is required to start. Exception to this are hydro electric black start units which are likely to be located remotely from other units. Hydro plants use the water to run the generator up to speed. However they must also be able to supply the real and reactive power needed to restart other generators through the network.

 

Some further comments to those I provided earlier. The question related to a CCGT plant but the principles are the same for all generators. When a generator black starts it will effectively carry out a dead line close ie the system or the network is dead. The synchronising facility on the generator will have settings that allow the circuit breaker to close if the network side is dead. If the network side is alive then the synchronising facility will only allow the circuit breaker to close if the two systems are closely synchronised ie the voltage magnitude and angle on each side are within the limits set by the synchronising facility. If the voltage magnitude and angle are not within the limits then closure of the circuit breaker will be blocked. Note that some synchronising facilities provide the ability for the excitation and governor of the generator being synchronised to be automaticall adjusted. If the network side is alive but the generator side is dead closing of the circuit breaker is usually blocked to prevent a non-rotating generator being damaged.

 

Need to locate a couple of Eng. firms capable of performing Black Start Capabiity study for our customer, utility operating 6 hydro power plants.

Can you help?

 

We have developed a system suitible for black start capability of turbines by battery back-up. The main application of the UMD (Uninteruptible Motor Drives) is to provide uninterruptible power for standard 3-phase AC motors. Often it replaces the diesel engine and DC motors used as back-up of critical auxillary systems. If you have a predifined starting sequence with load list of the starting motor and the auxillary systems maybe we could provide you with a solution. Also the calculated time for the black start sequence is important to know in order to design a complete MCC unit with capacity to repeat the starting sequence in a given period of time. Please contact me by email if you are interested to recive more information.

BR
Johan A, johan.anicic [at] kraftelektronik [dot] se